In automotive applications, electrical switches are often used for controlling electro-mechanical systems such as power windows, sunroofs, door locks, power mirrors, etc. These switches may often be integrated into a console or door frame along with other components and accessories. Due to the repeated use of many of the electrical switches, durability and reliability are paramount. Moreover, a malfunctioning switch can prevent the use of an important feature such as the ability to open or close a door window.
In addition to reliability, cost is an important issue in incorporating electrical features in an automobile. The cost of producing an electrical switch for the above applications can be affected by the materials used, the number of parts used and the assembly process to name a few. Accordingly, the often competing objectives of providing a low-cost component that is durable and reliable needs to be balanced.
Various prior art window switches teach specific arrangements for implementing switches in an automobile. In particular, such prior art switches teach multi-functional switches using a single toggle or “actuator knob”. A single window switch may be used to provide dual-stage operation in both forward and rearward directions. The common application for such switches is to provide manual and automatic window operation for opening and closing same, wherein the application of a first force operates the window switch in a manual mode, and the application of a second force, being greater than the first force, operates the window switch in an automatic mode. Typically by applying the second force, the window continues to open without further tilting of the actuator knob. Generally, these window switches offer tactile feedback to the user enabling the user to discern between the manual mode and the automatic mode.
Examples of the above type of prior art switches are shown in U.S. Pat. No. 6,737,592 to Hoang et al., published on May 18, 2004; U.S. Pat. No. 6,914,202 to Sugimoto et al., published on Jul. 5, 2005; and U.S. Pat. No. 5,719,361 to Lee, published on Feb. 17, 1998.
In some switches, such as that shown in Lee, collapsible elastomeric domes are operated on by a actuator knob to bridge contacts on an underlying circuit board to in turn operate the switch. The elastomeric domes will often have a limited lifespan, which can vary according to the material used, the experience of any abnormal or irregular forces acting on the domes and the frequency of use. Abnormal and irregular forces can be affected by the actuating mechanism used and the force applied by the user and can cause the dome and thus the switch to fail prematurely.
There exists a need for an electrical switch that can address at least one of the above-described problems and provide a solution that balances cost and reliability.